The invention relates to a clutch for use in a transmission line of a vehicle, comprising a first and a second main part which extend coaxially in relation to each other and are rotatable about a common longitudinal axis, and which are non-rotationally connected to a drive shaft and a driven shaft respectively, wherein the first main part has a first and a second portion which are arranged at a distance apart in the axial direction, and a pressure plate and at least one pressure spring which are mounted between the first and the second portion, and the second main part has a clutch disc, the pressure plate and the clutch disc being axially movably connected to the drive shaft and the driven shaft respectively, and the pressure spring is mounted between the second portion and the pressure plate, attempting to bring the latter into frictional engagement against the clutch disc and simultaneously the clutch disc into frictional engagement against the first portion, and the clutch further comprises an actuator device which is arranged for engagement with the pressure spring, hereby reducing the spring force exerted by the pressure spring against the pressure plate in order to reduce the frictional engagements, where the actuator device is comprised in the first main part and has an axially movable body which is arranged between the pressure spring and the pressure plate, and via which the spring force is transferred to the pressure plate when the actuator device is not in operation.
From the prior art clutches are known in which the spring is a diaphragm spring or membrane spring which extends from the second portion to near the driven shaft. The actuator may be a hydraulic cylinder device which is provided inside a clutch housing, having a cylinder and a cylindrical piston disposed therein, through which the driven shaft can extend axially. On the piston there may be mounted a release bearing through which the driven shaft similarly extends, and via which the piston is connected to the radially inner portion of the diaphragm spring.
Alternatively, the actuator may be disposed outside the clutch housing and be connected to a release bearing via a mechanism.
Even though the drive shaft and the driven shaft nominally should extend coaxially, in practice this is only achieved within certain production tolerances. When the engine is running, therefore, a relative movement is obtained of the rotating components of the clutch""s main parts, which is undesirable as it can lead to vibration of the clutch, and this vibration can be transmitted to the vehicle in which the clutch is mounted. It may moreover result in excess wear on the clutch""s components.
Since the portion of the diaphragm spring which influences the pressure plate is normally located at the periphery of the pressure plate, and a radially inner portion of the diaphragm spring is influenced by the actuator, together with the fact that the intermediate portion of the diaphragm spring is elastically flexible, especially if this intermediate portion comprises radially extending fingers, the piston has to travel a great distance in order to release the clutch. The clutch""s axial length will thereby also be great and the clutch will be heavy and voluminous.
An object of the invention is to provide a clutch which is not encumbered with the above-mentioned disadvantages.
In DE-A-34 25 346 it is disclosed a friction clutch having a first main part, a second main part, a pressure plate being constituted by a first friction plate, a pressure spring, clutch discs on the second main part and an actuator device engaging the pressure spring to reduce the spring force exerted by the spring. The actuator device is comprised in the first main part and has an axially movable body which is arranged between the pressure spring and the pressure plate and via which the spring force is transferred to the pressure plate when the actiator device is not in operation. This clutch comprises an opening in a stationary outer housing, which may be connected to a fluid supply.
The clutch according to the invention differs from this known device in that it comprises a swivel being arranged between the actuator and the driven shaft. By this arrangement the outer diameter of the clutch can be kept to a minimum. The swivel is for transferring a pressure fluid or an electric current to the actuator which may be a hydraulic or electric actuator.
The characteristics of the clutch according to the invention are set forth in the characterising features indicated in the claims.